The JPEG committee didn't believe it was patent encumbered, but Sisvel came along and put together a portfolio of patents it claims must be licensed to use JPEG

The JPEG committee didn't believe it was patent encumbered, but Sisvel came along and put together a portfolio of patents it claims must be licensed to use JPEG XT. However, Sisvel at present is only claiming that devices with cameras have to license the patents. Sisvel did the same thing with VP9 and a couple of other recent video codecs.